Technical Field
This application relates to expandable sealing elements, such as packing elements, for use in operations in wellbores. More particularly, the application relates to a metal-to-metal sealing device and methods of use.
Background Art
Tools containing an expandable sealing element may be used to perform various operations or tasks in a wellbore. The expandable sealing element may be used to provide an annular pressure seal, a plug, a packer, a patch, on expandable tubing, as an anchor, tubing hanger, etc. For example, a packer tool is commonly used during wellbore operations to seal against pressure or isolate fluid. A packer tool is an expandable plug used to seal off an annular area around a tubing or casing section when cementing, acidizing, isolating, producing, etc., a formation zone. The packer tool is run into the wellbore, typically on a work string or production tubing. Sealing elements are expanded radially, and typically compressed axially, and seal the packer tool against the wellbore, cased or uncased. A packer tool typically consists of a sealing element or elements which are actuated by a setting assembly, one or more holding assemblies such as slips, and at least one interior passage for fluid flow.
Elastomeric materials are frequently used for packing and other sealing elements because of their resiliency. Elastomeric elements may be insufficient under certain conditions, such as high temperature, high pressure, and chemically hostile environments. A metal-to-metal contact between, for example, a sealing element and a casing is less prone to extrusion under such circumstances. However, typical manufacturing tolerances of the casing, deformation during transport and installation, etc., often lead to ovality, upsets, and other non-conformities, which tend to reduce the sealing capabilities of the metal-to-metal contact. Leakage, extrusion and other problems can result. Further, even if an initial seal occurs, the seal may leak under changing conditions of temperature and/or pressure.
Prior efforts, such as shown in U.S. Pat. No. 2,519,116, incorporated herein by reference for all purposes, to effect metal to metal contact have employed detonating explosive charges disposed on a rod within a packer cavity to expand an outer ductile metal wall of the packer. The expanded metal wall engages the casing and forms a metal to metal contact. Further, U.S. Pat. No. 2,306,160, also incorporated herein by reference for all purposes, teaches a fluid injected into a cavity to inflate the cavity and effect a seal. The reference discloses that suitable liquid materials injected into the cavity are liquids which harden after expansion. More recent efforts include U.S. Pat. No. 6,446,717, to White et al., which discloses a sealing assembly with a deformable portion and a core, at least partially disposed within the deformable portion, that can be radially expanded to engage an adjacent surface and effect a seal. In one embodiment, the core encases a compressible fluid and the deformable portion comprises a deformable metal. The core can retain an amount of stored energy and adjust to changing conditions that otherwise might affect seal integrity. U.S. Pat. No. 7,445,104, to Duhon, discloses an apparatus for use in a wellbore, comprising an element formed of a superplastic material to perform a predetermined downhole task. The apparatus can comprise a flowable element and a deformable element adapted to be expanded by flowing the flowable element. Installation methods can include running a tubular structure into a wellbore and activating a heating element to heat at least a portion of the tubular structure to enable the tubular structure to exhibit a highly deformable characteristic while maintaining structural integrity. The White and Duhon references are hereby incorporated herein in their entirety for all purposes.
Therefore, a need exists for a metal-to-metal sealing assembly with increased sealing capabilities and sufficient resiliency, particularly under adverse conditions in an oil field well. Further, a need exists for such a sealing assembly which is retrievable.